xref: /openbsd-src/gnu/llvm/libcxx/include/__algorithm/ranges_min.h (revision 4bdff4bed0e3d54e55670334c7d0077db4170f86)
1*4bdff4beSrobert //===----------------------------------------------------------------------===//
2*4bdff4beSrobert //
3*4bdff4beSrobert // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*4bdff4beSrobert // See https://llvm.org/LICENSE.txt for license information.
5*4bdff4beSrobert // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*4bdff4beSrobert //
7*4bdff4beSrobert //===----------------------------------------------------------------------===//
8*4bdff4beSrobert 
9*4bdff4beSrobert #ifndef _LIBCPP___ALGORITHM_RANGES_MIN_H
10*4bdff4beSrobert #define _LIBCPP___ALGORITHM_RANGES_MIN_H
11*4bdff4beSrobert 
12*4bdff4beSrobert #include <__algorithm/ranges_min_element.h>
13*4bdff4beSrobert #include <__assert>
14*4bdff4beSrobert #include <__concepts/copyable.h>
15*4bdff4beSrobert #include <__config>
16*4bdff4beSrobert #include <__functional/identity.h>
17*4bdff4beSrobert #include <__functional/invoke.h>
18*4bdff4beSrobert #include <__functional/ranges_operations.h>
19*4bdff4beSrobert #include <__iterator/concepts.h>
20*4bdff4beSrobert #include <__iterator/projected.h>
21*4bdff4beSrobert #include <__ranges/access.h>
22*4bdff4beSrobert #include <__ranges/concepts.h>
23*4bdff4beSrobert #include <initializer_list>
24*4bdff4beSrobert 
25*4bdff4beSrobert #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26*4bdff4beSrobert #  pragma GCC system_header
27*4bdff4beSrobert #endif
28*4bdff4beSrobert 
29*4bdff4beSrobert #if _LIBCPP_STD_VER > 17
30*4bdff4beSrobert 
31*4bdff4beSrobert _LIBCPP_PUSH_MACROS
32*4bdff4beSrobert #include <__undef_macros>
33*4bdff4beSrobert 
34*4bdff4beSrobert _LIBCPP_BEGIN_NAMESPACE_STD
35*4bdff4beSrobert 
36*4bdff4beSrobert namespace ranges {
37*4bdff4beSrobert namespace __min {
38*4bdff4beSrobert struct __fn {
39*4bdff4beSrobert   template <class _Tp, class _Proj = identity,
40*4bdff4beSrobert             indirect_strict_weak_order<projected<const _Tp*, _Proj>> _Comp = ranges::less>
41*4bdff4beSrobert   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
operator__fn42*4bdff4beSrobert   const _Tp& operator()(const _Tp& __a, const _Tp& __b, _Comp __comp = {}, _Proj __proj = {}) const {
43*4bdff4beSrobert     return std::invoke(__comp, std::invoke(__proj, __b), std::invoke(__proj, __a)) ? __b : __a;
44*4bdff4beSrobert   }
45*4bdff4beSrobert 
46*4bdff4beSrobert   template <copyable _Tp, class _Proj = identity,
47*4bdff4beSrobert             indirect_strict_weak_order<projected<const _Tp*, _Proj>> _Comp = ranges::less>
48*4bdff4beSrobert   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
operator__fn49*4bdff4beSrobert   _Tp operator()(initializer_list<_Tp> __il, _Comp __comp = {}, _Proj __proj = {}) const {
50*4bdff4beSrobert     _LIBCPP_ASSERT(__il.begin() != __il.end(), "initializer_list must contain at least one element");
51*4bdff4beSrobert     return *ranges::__min_element_impl(__il.begin(), __il.end(), __comp, __proj);
52*4bdff4beSrobert   }
53*4bdff4beSrobert 
54*4bdff4beSrobert   template <input_range _Rp, class _Proj = identity,
55*4bdff4beSrobert             indirect_strict_weak_order<projected<iterator_t<_Rp>, _Proj>> _Comp = ranges::less>
56*4bdff4beSrobert     requires indirectly_copyable_storable<iterator_t<_Rp>, range_value_t<_Rp>*>
57*4bdff4beSrobert   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
operator__fn58*4bdff4beSrobert   range_value_t<_Rp> operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const {
59*4bdff4beSrobert     auto __first = ranges::begin(__r);
60*4bdff4beSrobert     auto __last = ranges::end(__r);
61*4bdff4beSrobert 
62*4bdff4beSrobert     _LIBCPP_ASSERT(__first != __last, "range must contain at least one element");
63*4bdff4beSrobert 
64*4bdff4beSrobert     if constexpr (forward_range<_Rp>) {
65*4bdff4beSrobert       return *ranges::__min_element_impl(__first, __last, __comp, __proj);
66*4bdff4beSrobert     } else {
67*4bdff4beSrobert       range_value_t<_Rp> __result = *__first;
68*4bdff4beSrobert       while (++__first != __last) {
69*4bdff4beSrobert         if (std::invoke(__comp, std::invoke(__proj, *__first), std::invoke(__proj, __result)))
70*4bdff4beSrobert           __result = *__first;
71*4bdff4beSrobert       }
72*4bdff4beSrobert       return __result;
73*4bdff4beSrobert     }
74*4bdff4beSrobert   }
75*4bdff4beSrobert };
76*4bdff4beSrobert } // namespace __min
77*4bdff4beSrobert 
78*4bdff4beSrobert inline namespace __cpo {
79*4bdff4beSrobert   inline constexpr auto min = __min::__fn{};
80*4bdff4beSrobert } // namespace __cpo
81*4bdff4beSrobert } // namespace ranges
82*4bdff4beSrobert 
83*4bdff4beSrobert _LIBCPP_END_NAMESPACE_STD
84*4bdff4beSrobert 
85*4bdff4beSrobert _LIBCPP_POP_MACROS
86*4bdff4beSrobert 
87*4bdff4beSrobert #endif // _LIBCPP_STD_VER > 17 &&
88*4bdff4beSrobert 
89*4bdff4beSrobert #endif // _LIBCPP___ALGORITHM_RANGES_MIN_H
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